Pile Of Environmental Effects And Control Technology Research

CFG pile stands for cement, fly ash and gravel, which mix together to a kind of concrete pile. CFG pile is made up of cement, fly ash, gravel and sand with water, which composes the composite foundation with soil and cushion. The research work of CFG pile composite foundation is a very important task in the seventh five-year project supported by ministry of construction. The set of technology was widely introduced in the whole country in 1994. In order to father spreading the new technique, the construction facility and technology are specially studied and financially supported by the government. It also has been included in the key problem of the ninth five-year project. The set of CFG pile with long screwy drill pipe inner pump pressure was checked and accepted by state in Dec, 1999. Now, CFG technology has totally transferred from driven caisson pile to long screwy drill pipe inner pump pressure.Compared with other commonly used piles, the body material of CFG pile can be mixed with waste industrial fly ash, and without reinforcing bars, Whereas this kind of material can also fully exert the bearing capacity in the soil. Moreover, the cost of CFG can reduce to 1/3~1/2 price of other piles. So from the aspects of economical and social benefit, it has a lot of advantages. On the other hand CFG pile with long screwy drill pipe inner pump pressure is low noisy and without muddy water pollution; The process of drilling will not lead to vibration and has the capacity to penetrate hard rock layer; Also the construction is of high efficiency. Therefore it has been widely used in the whole country and has been regarded as a common foundation solution technology.However in the haugh area of Zhengzhou with high level underground water > easily flowing silt or mealy sand layer, CFG pile has induced serious environmental geotechnical engineering problem . The main reason is unclear to the theory of how CFG pile impacts the surrounding environment. Besides, the law of surrounding environment displacement and settlement is not evident and it's hard to control the displacement and settlement.This paper analyses the working principle of CFG pile composite foundation and construction technology, especially focuses on the comparison with other piles in construction skills. Aiming at the geological characteristic of haugh in Zhengzhou, the theory of seepage deformation and the pore expanding were applied in the research work of CFG pile impacting the surrounding environment. Then the controlling solution was listed in the paper.The main achievements and conclusions of this paper are summarized below:1) Contraposing the engineering geological structure of haugh, the working principle of CFG pile with long screwy drill pipe inner pump pressure impacting the surrounding environment was raised in the paper. Summarized as follows: 1) the inside pile is vacuum 2) the empty pile is too long 3) under the pump pressure, mixed materialhas the super pore water pressure influence on the surrounding soil.2) According to the hydrological geological situation and engineering characteristics of haugh ,the range of influencing area impacted by CFG pile with long screwy drill pipe inner pump pressure was researched and analyzed in the paper and the corresponding calculated formula and conclusion were found.3) The technical methods of controlling CFG pile construction environment deformation and settlement were raised in this paper. Those are bottom ringent aiguille technics ,composite soil-mailing wall technique ,and so on.